2015 Little America's Cup

Discussion in 'Multihulls' started by Doug Lord, Apr 14, 2014.

  1. Doug Lord
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  2. Navygate

    Navygate Previous Member

    Oh, those Canadians 'eh ! ! !
     
  3. Doug Lord
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    Story tonight from Scuttlebutt on the next LAC: http://www.sailingscuttlebutt.com/2...letter&utm_term=Class C On the road to Geneva

    To be known as the LITTLECUP*, the 27th edition of the event will be hosted by Société Nautique de Genève in Geneva, Switzerland from 12 to 19 September.

    *Not by me ever: it will always be the Little America's Cup!

    An excerpt from the article:

    In order to defend their trophy in the best possible conditions, Groupama sailing team and its design office have been putting in the hours: “We’ve identified two main points of evolution: the ergonomics and the aerodynamics of the trampoline and also the appendages, namely the foils and the rudders,” explains Louis Viat, Franck Cammas’ crew and also team manager since Stéphane Guilbaud’s departure.

    Dividing his time on the water with either Franck or Julien Villion at the helm off the team’s Lorient base, Louis is well placed to judge how things are progressing: “The work on the trampoline was aimed at simplifying manoeuvring so as to exploit the full potential of the boat. We’ve also streamlined the systems and made some aerodynamic gains,” adds Louis.

    Another area of development is the appendages: “We’ve kept the port foil from 2013 and we’ve designed a new starboard foil in-house. We’re happy with how it feels, but that’s not enough for us. Groupama C is brimming with sensors, which should enable us to develop a significant analysis procedure from the data collected. We’re sailing in 2-minute phases, modifying one element each time.
     
  4. Doug Lord
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  5. Doug Lord
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    2015 Lac

    Seems awfully quiet when it's just a few months away?
     
  6. Doug Lord
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    From MA by Steve Clark ,6/22/15:

    No one seems to answer so I guess I will.
    Event is shaping well, buit will be slightly less well attended than Falmouth.

    The Royal Canadians: Fill Your Hands, sailed by Billy and Norm, New foil package.
    --
    Groupama: Franc and Louis, refined championship boat.
    --
    Hydros 1 &2 both entered but I don't know who is sailing them. Both have new pieces but I don't know specifics.
    --
    Sentient Blue, Now German, using Heemskerk foils on 2007 platform and wing. Don't know who is sailing, could be Paul and Helena.
    --
    Les Quebecois: Boat racing to the race. http://etsclassc-rafale.ca/

    --
    AXON Racing: Sailing Cogito. Boat as sailed in 2013, but actual french will be spoken aboard instead of MacLane's Inspector Clouseau ( CHEIF Inspector Clouseau) style french. Benoit Marie and Benoit Morrelle are training with Clark in the US in July and providing local knowledge in September.
    --
    Aethon USA 105, re-grooved for the event with new foils, canting wing and a few other small tricks. As always, we are trying to out think everyone. Steve Clark and Mike Costello. Wing testing going OK, new foils showing up any day, hulls would float now, lotts of other boxes to check. Our stack of Manana cards is waffer thin.
    ==================
    Not showing up:

    Invictus Conserving assets and energy for a new build, which weill be delayed until the last possible moment and then will only make it as the result of heroic effort.
    --
    Flying Frogs Won't be shipping PLVI to the alps, and hasn't got the mojo to do anything better.
    --
    City Of Cascais Portugese boat that made a ceremonial appearance and beam failure at Falmouth..... Sorry but who builds a hollow, curved dolphin striker strap? Who thinks it is a good idea?
    --
    Itallia Team from Scily has gone dark, no word ion a while, I think there are some pretty decent hulls there and mnaybe tooling for good wings, but nothing on the water. Lots of promise but no delivery.
    --------

    I don't know anything more: It seems that someone would put a big rig on a Phantom and try to humiliate us, but I don't think there arte any other actuall C Class catramarans out there that could or would show up.

    SHC

    Beatings will continue until morale improves.
     
  7. Doug Lord
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    Doug Lord Flight Ready

  8. Doug Lord
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    Little America's Cup--Sept. 12-20 2015

    The Little America's Cup website: http://www.littlecup.org/en/

    Teams: http://www.abcclass.net/equipes-2015.php NOTE-on MA Steve Clark says his new boat is Aethon USA105--not Cogito 2015........

    Schedule:
    - September 6-11
    Measurement
    - Thursday 10th September
    12:00 Mandatory presence of all teams and C Class boats
    Welcome Briefing for all Teams
    14:00 training Day , C-Class branding
    - Friday 11th September
    Last Day for issuing C-Class measurement certificates
    - Saturday 12th September
    12:00 Team Briefing
    - Between 13 and 20th September
    Little America's Cup Races.
     
  9. Doug Lord
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    Aethon USA 105

    Steve Clarks new boat has intensely long main foils-nearly from the lee hull to the windward hull and pretty shallow. Very innovative system. Also note the small wingtip foil......
    ----
    from MA by Steve Clark:
    "Finally have some renderings of what we are bringing.
    1)SNAKEfOILs: Low drag foil solution which can be pulled all the way up on the windward side.
    Longer span, less induced drag, less spray and parasitic drag plus we don't have to fly 1 meter in the air. Splashes are much less dramatic as a result.

    Down side is the center of lift is further inboard, so we give up some righting moment. Foil also works near the surface and can ventilate if we don't pay close attention.
    2) Wing re-profiled and twist rebuilt repaired. Wing lowered to end-plate to trampoline.
    3) 3di trampoline sealed to centerline of hulls, and with end plating of wing provides significant up force out of trampoline, improved driving force from wing and lower induced drag. Numbers from study are stupidly big. I really find it hard to believe what the machines are telling us, but if it is even half true....
    4) Main beam fairing far more aggressive than last time, to try to get some positive camber into the trampoline and get a good seal with minimum sail area.
    Weight hasn't improved, but that's what happens when you substitute 18 kg hydrofoils for 5 kg centerboards. I am 10 kg lighter however and mike weighs about 15 kg less than Oliver

    We have a metric shitload to figure out, and not a lot of time before they start scoring, so I expect we are well behind. Hopefully we can catch up and make it somewhat interesting. So far the testing has been a complete gas or as frustrating as anything I have ever done on the water. Sometimes the difference is really small.

    SHC "

    [​IMG]

    [​IMG]
     
  10. rcnesneg
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    rcnesneg Senior Member

    Very impressive! I hope they do some serious filming!
     
  11. Doug Lord
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    SnAkefOIL

    I have been inspired by Steve's Snakefoil concept. It occurred to me that since the foil goes almost all the way across the boat, why not go to a single foil instead of two very long foils. Might be lighter?

    Note: I based this idea on the render above of Steves foil. That render seems to show the foil as longer than it really is or is an optical delusion based on the angle of the boat in the render. Since a C Class is 14' wide my foil idea is probably not practical-I haven't done any calculations at all-just based it on what I thought I understood from the render. I was wrong.

    [​IMG]
     
    Last edited: Aug 27, 2015
  12. Doug Lord
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    SnAkefOIL

    This illustrates the foiling waterline and shows that it would have the same drawback Steve mentions with his foil-the center of lift is further inboard than with a "normal" foil. But the angle of the surface piercing foil can have a substantial vector of lift to weather. Steve points out that with a foiler that's in the air actually moving("crabbing") to weather is not the detriment it is on a seahugger.

    [​IMG]
     
  13. Doug Lord
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    SnAkefOIL

    Dave Clark sheds light on this interesting foil:

    Doug, your enthusiasm is great. Keep on pluggin'. But no. The intent of the SNAKEfOIL is actually not to get foiling sooner. There is no judge awarding points for simply being out of the water more. The boat has exited the water in light winds sooner than would be expected, but that was mainly a function of maxing out the foil trim and was on final analysis simply wasted energy picking up the boat. It definitely brought it below a fast catamaran's displacement-mode speed for that wind. In fact, I believe my dad's intent is the reverse of your assumption. The SNAKEfOIL (named for the board head's resemblance to that of a cobra, the caps bit is a self deprecating joke i.e. "snake oil") is a seven foot long slightly recurved straight board with a tightly curved head that acts as a cant control. This means that the board can be reverted to a cant angle of zero and simply zip along in displacement mode on the leeward side and be fully retracted from play on the windward side. This solves too problems in wind speeds where foiling is pointless. First, it eliminates the excess drag found in the horizontal component of a stereotypical catamaran hydrofoil when in displacement mode. This excess drag was poison to hydros in light air and Mischa went to arguably radical lengths to combat it. Second, the unretractable component of the stereotypical catamaran hydrofoil is a pain on the windward side in light air. It juts out sideways and drags just as you are starting to build speed and fly a hull. Ideally, the SNAKEfOIL should make it possible to glide along in sea-hugger mode in light air and foil in good breeze. That said, if the breeze is light, my money is on Cogito. She's the best boat for a drifter in the event, Benoit Marie knows what he's doing with the stick and Benoit Morelle is a seasoned veteran of strange lake geneva breeze. Let's bit forget that this is a boat race. I hope I've brought some clarity to all this.

    DRC
     
  14. Doug Lord
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    SnAkefOIL

    Steve Clarks comments on the following illustration of how the Snakefoil is used. Keep in mind that this foil is used as a single surface piercing foil :
    As you can see it acts just like an deep asymmetrical dagger board until we engage the head. Then it becomes a canted surface piercing foil.
    A subtly is that the radius under the hull gets it deeper than if it was simply inclined in a straight trunk.
    The head of the board is also symmetrical, which makes it quite fat for structure, but also reduces lift right at the surface, so it is less likely to gulp air. It also makes the boat more docile as the waterline travels up and down the curved span.
    The reflex curve is so that the foil loses vertical projected area faster than it loses sideways projected area as the boat rises out of the water. We only intend to fly 12" or so in the air. Lots less windage down there. And the bow and stern are a whole lot more useful when things go wrong.

    Paul Bogataj deserves all the credit for taking my various musings, observations, prejudices and observations and turning them into a coherent design. It is said a million times that design is all about compromise, inn this case I was willing to surrender righting moment for less drag and to not have extra wetted surface in light air and the giant sucking sound when the windward hydrofoil breaches the surface during the most critical part of the speed build.

    Erich Chase built the boards, and did his usual great work.

    It should be fun to see what happens if we get any wind at all.
    SHC
     

    Attached Files:


  15. Doug Lord
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